The invention is concerned with an apparatus for the positioning of heavy objects, particularly rolls of paper or other weblike materials, comprising of a clamping fixture for the roll or other object to be positioned, eg, turned over, and a swivel mechanism. Such swivel devices are known for use as load-receiving appliances and as auxiliary equipment of cranes and forklift trucks. They have the task of moving the roll or other object from a position brought about by a prior processing or transporting step into a new processing or transporting position.
In the case of cylindrical bodies, like rolls of paper, plastic or metal, devices exist already which grip from the front side, whereas in the case of platelike objects the surface pointing upward is usually clamped. The swiveling of objects clamped in such a way takes place up to now around an axis which lies outside the one which goes through the common center of gravity of the object and the co-rotating part of the device. This has the disadvantage that the position of the common center of gravity is changed during the swinging operation. When the center of gravity travels downward, energy of the position has to be absorbed or converted respectively, whereas when the center of gravity travels upward, lifting energy is required. Such devices are therefore expensive not only as far as their construction is concerned, but their control mechanism together with the hoisting gear belonging to it is also relatively complicated. Beyond this, manipulating these devices, particularly those with internal clamping, requires skill in the releasing and clamping of the objects.
The invention is therefore based on the task of producing an apparatus in which, independent of the way in which the object is unilaterally gripped, the common center of gravity of the object and of the parts moving together with it in the swinging remains on the same level during the entire swinging operation.